This invention relates generally to gas turbine engines, and more specifically to a method and apparatus for detecting impending sensor failure.
At least some known gas turbine engines include a compressor, a combustor, and at least one turbine. The compressor compresses air which is then channeled to the combustor. The compressed air is mixed with fuel and ignited within the combustor to generate combustion gases which are channeled to the turbine. The turbine extracts energy from the combustion gases to power the compressor, as well as to produce useful work to propel an aircraft in flight or to power a load, such as an electrical generator.
At least some known engines also include a plurality of sensors for monitoring operating conditions related to the engine. For example, the engine may include sensors that monitor temperature, pressure, speed, flow, displacement, and strain. During operation, the sensors may be exposed to adverse environmental and operating conditions, such as temperature extremes, vibration, and combustion gases. Over time, continued exposure to such conditions may cause a premature failure of some of the sensors, which may adversely impact the operation of the engine and airframe. To facilitate reducing the failure rate of engine sensors, at least some known gas turbine engines include redundant sensors in critical applications, and/or monitoring system which monitor the sensor output signals. More specifically, at least some known gas turbine engines operate with sensors that are replaced after failure or based on predetermined sensor values, or include sensors that are replaced on a regular schedule regardless of the operating capability of the installed sensor. However, such methods may not provide desired results, and waiting for a sensor to fail to replace it, or replacing an operating sensor based on a time or operating hours schedule may be costly and time-consuming.
In one aspect, a method for detecting an impending failure of a process sensor is provided. The method includes determining a sensor output noise component, and comparing the output noise component to a historical sensor output noise signature based on at least one of the range of span of the sensor and the process operating conditions.
In another aspect, a method for detecting an impending failure of a gas turbine engine sensor is provided. The method includes sampling the sensor output for a predetermined time period to obtain a representative sample of the output signal, determining a current sensor output signal, determining a range of span of the sensor, determining a sensor output noise component, and comparing the output noise component to a historical sensor output noise signature based on at least one of the range of span of the sensor and the engine operating conditions.
In yet another aspect, an apparatus for a gas turbine engine that includes a computing device is provided. The computing device includes a processor, and a memory communicatively coupled to said processor wherein the processor is programmed to execute a software product code segment that includes a comparator, a data historian, an isolator module, and a limit module and wherein the computing device is programmed to detect impending failure of a sensor using an output signal noise component of the sensor and wherein the sensor senses a parameter of a process associated with the computing device.